多尺度TiB/Ti_(2)AlN颗粒相增强TiAl合金组织与力学性能研究

Study on the Microstructure and Mechanical Properties of TiAl Alloys Rein⁃forced with Multi-Scale TiB/Ti_(2)AlN Particles

在Ti43Al6Nb1Mo合金中加入BN增强体,设计出多尺度颗粒增强TiAl复合材料,研究合金中多尺度、多组分硼化物和氮化物颗粒相形成机制以及颗粒相对合金凝固组织的影响规律,探究多尺度颗粒相的协同强韧化机制。结果表明:Ti43Al6Nb1Mo-xBN复合材料中原位自生形成了Ti_(2)AlN相和TiB相,加入BN增强体后,合金片层团尺寸细化明显,这主要是由于Ti_(2)AlN相和TiB相的协同细化效应。另外,Ti_(2)AlN相和TiB相的形成有效抑制了B2相的形成,当BN含量为0.5wt%时,B2相消失。多尺度Ti_(2)AlN和TiB相诱发细晶强化效应、抑制B2相形成,产生固溶强化效应以及第二相沉淀强化效应,Ti43Al6Nb1Mo-xBN复合材料表现出优异的室温和高温强塑性,实现TiAl合金强度和塑性的良好匹配。

This study involves incorporating BN reinforcement into Ti43Al6Nb1Mo alloy to design multi-scale particle-reinforced TiAl composites.The research aims to investigate the formation mechanisms of multi-scale,multi-component borides and nitrides in the alloy,as well as the influence of particle phases on the solidification mi-crostructure of the alloy.Furthermore,the study explores the synergistic strengthening and toughening mechanisms of multi-scale particle phases.The results indicate that in Ti43Al6Nb1Mo-xBN composite materials,Ti_(2)AlN and TiB phases are formed in situ.The addition of BN reinforcement leads to a significant refinement in the size of alloy grains,primarily due to the synergistic refinement effects of Ti_(2)AlN and TiB phases.Additionally,the formation of Ti_(2)AlN and TiB phases effectively suppresses the formation of the B2 phase,which disappears when the BN content is 0.5 wt%.The multi-scale Ti_(2)AlN and TiB phases induce grain refinement strengthening effects,inhibit the forma-tion of the B2 phase,and generate solid solution strengthening effects as well as second-phase precipitation strength-ening effects.The Ti43Al6Nb1Mo-xBN composite materials exhibit excellent room temperature and high-temperature strength and ductility,achieving a good balance between strength and plasticity in TiAl alloys.